/Engine/Plugins/Protocols/MQTT/Source/MQTTCore/Public/IMQTTClient.h
Only for single sub
template<typename CallableType> [TFuture](API\Runtime\Core\Async\TFuture)< [FMQTTSubscribeResult](API\Plugins\MQTTCore\FMQTTSubscribeResult) > Subscribe ( const [FString](API\Runtime\Core\Containers\FString) & InTopicFilter, CallableType && InOnMessage, [EMQTTQualityOfService](API\Plugins\MQTTCore\EMQTTQualityOfService) InQoS )